Dumbbell



FIG. 1 is a front perspective view of a dumbbell according to the present design.

FIG. 2 is an end view thereof.

FIG. 3 is an opposite end view thereof.

FIG. 4 is a front view thereof.

FIG. 5 is a rear view thereof

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

The broken lines shown in the figures are for the purpose of illustrating portions of the dumbbell, which form no part of the claimed design. 

CLAIM The ornamental design for a dumbbell, as shown and described. 